Telephone-exchange system.



,M. S. GONNER. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JAN. 24, 1966.

Patented Oct. 20, 1908* Ewe ur" Q N m ww 3 W asses:

MEPFI'II 5- Elunnr DIE-LEE.-

UNITED STATES P TENT OFFICE.

MERRITT s. GONNER, or nocniis'rnn, NEW YORK, Assi'euoa TO STROMBERG-CARLSON TELE- PHONE MANUFACTURING COMPANY, or noeursren, NEW YORK, A conronarxou or NEW YORK.

'rnLn-rnonn-nxomoz srs'rnu.

Specification of Letters Patent.

Patented Oct. 29, 1908.

Application filed mm as 1906- aaun Nonew.

State of New York, have invented a certain,

new and useful Improvement in Telephone- Exchange Systems, oi which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to cord circuits and particularly to such as are used in long-distance or toll systems, and its object is to provide a universal cord circuit which may be utilized to make the different connections called for in such'systems, and to provide supervisory means to meet the different conditions of operation.

In long-distance telephone service it is usual to provide the operator with cord pairs which are used to connect one toll line with another toll line and to provide a clearingout signal whichwill respond to the signal current apparatu usually supplied to the'different toll stations. This clearing-out or supervisor, signal is usually a dropor relay which will respond to alternating current. In some cases it is desired -,to con nect the long-distance line with a local or subscrihers station, which local stations are usually, under present practice, fed from a common battery at the central exchange. In this case it is usualto provide between the toll operator and the main switch-board, containing the local sub-stations, trunk lines,

- each terminating at the main board in a plug, and at the toll .operators position, 1n a jack. "The toll operator, when a long-dis tance line is to be connected with a local usually provided with some type of automatic signal which will indicate when the subscriber at the local station has answered.

The su ervisory arrangement tor connections of the above kind have heretotore been complicated and expensive, there {being special devices and arm; ments necessary for each .of the above con itions of connection, and it the object at my invention to combine these several supervisory features into More pair may used regard-less of the connection and which will automatically provide the proper clearing-out or supervisory si nal's tomeet these difl'erent connections an conditions of signal.

My invention will be better unders oo by reference to the accompanying drawing which diagrammatically illustrates a main stationv and a toll station, and the various connections which will be required and the universal supervisory means therefor.

Conn ctedwith the toll exchange. T are shown the sub-stations A and B'e.ach provided with the usual telephonic apparatus, comprising the switch hook 1, telephone receiver 2, transmitter 3 and battery 4, the sig- I131 hell 5, and the generator 6. The signal 5 and the generator are both connected in bridge ofthe line limbs a and b, the generator circuit, however, being normally open.

At the toll exchange the line limbs a, b, are shown as normally connected, through the.

armatures 7 and 8 of the cut-oil? relay 9, with the indicating relay 10, and thus upon actua tion of the sub-station generator the indicating relay will he actuated to convey a signal to the operator. The jack springs'll and 12 are respectively connected with the line limbs a and I), while the'jack thimble 1:3 connects through the winding .of the supervisory relay 9 with the negative side of the common battery 14:.

The toll, cord circuit comprises the cord plugs 15 and 16, plug 15 having the tip contact 17., the sleeve contact 18, and the thimble contact 119, and the plug 16 having thewtip contact 20, the sleeve contact 21 and the thimble 22. The thimble contact 19 connects through the windin of the controlling relay 23 with the groun ed positive side of the common battery 14, while the thimble contact 22 connects through the winding of the controlling relay '24 also with the positive side of the battery 14. The plug contacts 17 and 18 connect through strands 25 and 26 with the middle springs 27 and 28 of the ringing key B 7, while the contacts 20 and 21 of the plug 16 connect through strands 2,9 and 30 with the middle springs 31 and :32 .of the ringing key R; A generator :33 of signaling current is connected with .the allternate'u-contacts .34 and '35, and upon actuationof either side of the ringing key r nging current may he sent through the correspond- .eord strands and plug contacts into the line connected with the plug. The middle springs 27 and 28 are normally in contact with the inner contacts 36 and 37 while the middle springs 31 and32 are normally in contact with the inner contacts 38 and 39 of the key R. The inner springs 36 and 37 connect respectively with the middle springs 40 and 41 of an auxiliary key K while-the inner springs 38 and 39 connect respectively with the middle springs 42 and 43 of the key K The-inner contacts 44 and 45 of the key K are normally in contact with the middle springs and are connected --together through a condenser 46; the inner-springs 47 and 48 are normally connected w'itl1, t he middle springs 41 and 42 and are connected together through condenser 48. Thus normally the tip cord strands 25 and 29'are continuous through the condenser 48'- and the sleeve strands 26 and 30 are normally continuous through the condenser 46. The inner springs 45 and 48 are also connected respectively with thearmatures49 and-'50 controlled by the controlling relay 23, and the inner springs 44 and 47 are also connected respectively with the armatures 51 and 52 controlled by the're'lay 24. Theba'ck contacts 53 and 54 of the armatures49 and 51 respectively are connected ether through the conductor 55, andtho-bac contacts 56 and 57 of the armatures '50and 52 respectively are connected together-through the conductor 58, and across the "conductors 55 and 58 is bridged the supervisory relay 59 controlling the local circults for the supervisory lamp 60.

The alternate contacts and-41f are con nected together-and with the conductor 55, while the alternate contacts 42' and 43 are connected together and with the conductor 5.8. The front contacts 61 and 62 of the armatures. 49 and 51 are connected together through'the conductor 63 and the front con-v tacts 64 "and 65 of the armatures 50 and 52 respectively are connected together through the conductor '66. Across the conductors 63 and 66 is bridged thewinding 67 of the supervisory relay 68. This relay 68 is also provided with a local circuit winding 69 for controlling the supervisory lamp 70.

The main springs 71 and 72 of the operators key 0 are connected respectively with the inner springs 45and 47 of the key *F'KtEand the operators receivers circuit 73 is'connected to the outer contacts 74 and 75 of this key, additional spring 76 connects with the spring 72 and normally engages the contact 77, the spring 76 being connected with the armature 7 8' of the supervisory relay 68, and the contact 77 being connected with the negative side of the battery 14. The local circuits controlling the superviscry lamp 70 are normally continuous through the operators key, but upon actuation of this key these circuits are broken upon. disengagement of the contact 77 from .the contact 112, the contact 111 being the auxiliary spring 76. The operators transmitter circuita: is inductively associated with the receivers circuit as shown. 1

The sub-station C connects through the limbs 0, d, with the main board M The limb c connects through the armature 78 of the cut-off relay 7 9 and through the winding 80 of the indicating relay 81, and with the positive side of the battery 14, while the limb d connects through the armature 82 of the cutoff relay and the winding 83 of the indicating relay and with the negative side of the battery 14. The line limbs connect also with the jack springs 84 and 85, the jack 'thimble 86 connecting through the cut-off relay 7 9 with the positive side of the battery 14. The indicating lamp circuit 6 is controlled by the indicating relay 81.

The trunk line at the board M terminates at one end in the tip and sleeve plug contacts 87 and 88 and at the other end terminates in the tip and sleeve jack springs 89 and 90. The cord circuit is divided into two conductivelyseparate but inductively related sections, the jack springs 89 and 90 being connected together through the windings 91 and 92 of the repeating coils 93and 94 respectively, with the condenser 91 interposed between the windings, While the tip and sleeve contacts 87 and 88 of theplug may be connected through the windings 95 and 96 of the repeating coils 93 and 94 respectively, a condenser 97 being interposed between the windings. The operator ringing circuit is connected with the alternate contacts 98 and 99 for the middle springs 100 and 101. The winding of a controlling relay 102 is connected with the negative side of the battery 14 and witlithe normal contact l03for the middle spring 101. The normal contact 104 for the middle spring 101 connects with the armature 105 controlled by the relay 102, and the front contact 106 for the armature 105 is connected with the winding 95. The outer terminal of the winding 96 connects with the normal contact 103.

An additional controlling relay 107 is associated with the trunk circuit and connected with the contact 106 of the relay 102 and with the positive side of 'the battery 14. The

armatures 108 and 109 controlled by this re lay are connected directly together by the,

conductor 110. -Upon .energization'of the rea the contacts engages with the contact 111 and is conne coil inding 91, while the contact 119 nor mall engages with, the contact/112 and is I conected with the inner end of the repeating coil winding 92. Upon energization of the relay 107 the armatures thereof. engage with 111' and 112 and cause disconnection of these contacts from the contacts 118 and 119 respectively.

Having thus secured the general disposition of the apparatus and circuits, the opera tion of this system becomes apparent.

osingsub-station A desires connection with toll sub-station B the subscriber at sub-station A actnates his generator to send an impulse through the indicating relay or drop 10, which will display a signal to the toll operator who then inserts plug 15 in the jack connected with the line leading to sub-station A. Upon such connection the i following circuit willbe closed: from buttip contact 17,

27 and 36, conductor 124, springs 41 and .48

tery 14 through conductor 120, conductor 121, cut-off relay 9, jack thimble 13, plug contact 19, conductor 122, controlling relay 23 and through conductor 123 to the positive side of the battery. Upon closure of this circuit cutoff relay 9 becomes energized to withdraw its armatures 7 and 8 to disconnect the indicator 10 from the line and controlling relay 23 is energized to attract its armatures into engagement with the contacts 61 and 64;. The winding 67 of the supervisory relay 68 connected with the conductors 63 and 66, is thereupon connected in bridge of the cord strands and line limbs a, I), through the following circuit: line limbo, jack spring 11, cord strand 25, keysprings armature sound to key K conductor 125,

contactconductor 63 to contact 61 and armature 49 of the relay 23, conductor 126, springs 45 and 40 of the key K conductor 127, springs 37 and 28 of the ringing key R, cord strand 26, sleeve contact 18, jack spring 12 and to line limb b, the circuit being ready to transmit ringing-ofi currents from the generator at sub-station A, upon cessation of conversation.

Having inserted the plug the operator actuates the operators key 0 to connect herself in circuit to ascertain the connection desired by the calling sub-station, and this being the sub-station B, she inserts the plug 16 into the jack J corresponding to substation B. Upon such connection the following circuit will be closed: from battery 14, through conductor 128, relay 9' to jack thimble-13, to the plug contact. 22, conductgr 129, controlling relay 24 and through conductor-129 to battery 14. Cut-ofli relay 9 is actuated to disconnect the indicating relay 19' from the line,-while con- Sup- 47 and 42, through 64 of relay 23, conductor 66, through; the plug spring pick to line through cut-ofi trolling relay 24 is energized to attract its armatures into engagement with contacts 62 and 65 to connect the winding 67 in bridge also of thecord strands 29 and 30 and the line leadin to sub-station B thecircuit being as to lows: line limb a, to jack spring p t p ringing key to conductor 180, through key K to conductor 131, through armature 52 and contact 65 of the relay 24, through conductor 66, through winding 67 to conductor 63, through contactv 62 and armature 51 of the relay 24, through conductor 132, through. the key K, conductor 133, through key R to cord strand 30, to sleeve contact 21,

through jack spring 12and to line limb b. The supervisory relay 68 will be thus in readiness to be actuated. upon actuation of the generator at the sub-station B when conversation is closed. Having thus connected with the desired line, the operator actuates the ringing'key R to send ringing current from the generator 33 tothe contact 35, cord strand 29, tip 20,- jack spring 11, through'the line limb a, through the bells 5 at sub-station B, through, line limb I), through jack spring 12, plug sleeve 20, cord strand 29, through the contact 21, cord strand 30, contact 35, back I to the generator 33. I

Upon removal of the receiver from the hook by the subscriber at sub-station B,

this sub-station and the calling station A will be in connection for telephonic conversation through the following path: line limb a, through the spring jack and associated plug to cord strand 25, through conductor 124, springs 41 and 47 ot" the key K, through the condenser conductor 130, through ringing'key R cord strand 29, through and associated spring jack to line through the sub-station telephonic limb a apparatus back to line limb 1), through the spring jack and associated plug to cord strand 30, through key R conductor 133, springs 43 and 44 to key K through condenser 46, through springs 45 and 40, conductor 127, through key R through cord strand 26,'through the associated plug and limb b and through the telephonic apparatus at sub-station A back to line limb (1. Upon cessation of conversation the subscriber either at sub-station A or B causes actuation of the generator .thereat' to send ringing-off current through the line and circuits at the central station before traced to cause energization of the supervisory relay 68 by means of the winding 67 This generator current is alternate in character and the local wind-ing 69 heretofore described is therefore provided to main 'iin energization of the supervisory relay. Upon actuation of this relay by the winding 67, its armature 7 8 is attracted to 48, through springs through key K,

' positive 101 and 103 to relay side of battery 14,

ductor 138, lamp 70, contact 134 and arma-' ture 78' to conductor 136, contacts 76 and 77 of operators key and through conductors 137 and 120 back to the battery. Upon receiving this signal the operator withdraws both plugs from the jacks. Although .the local circuit controlling the lamp '70 still remains closed after withdrawal of the ')lugs, the operator can easily restore the circuit by tapping the operators key to open the contacts 76 and 77, whereupon relay 68 becomes energized and the circuits are all again in their normal condition.

If the calling sub-station A had desired connection with a local common battery stationfo r instance C the toll operator would notify the trunk operator of the desired connection and the trunk operator would inform her of the trunk to be used andwould insert the plug of this trunk into the spring jack connected to the sub-station C Immediately upon connection of this plug in the jack current will flow from the side of battery 14, through conductor 139 to relay 79, through jack thimble 86, sleeve contact 88, cord strand 140, springs 102, through conductor 141 to the negative side of-battery 14, the cut-off relay necting the indicating relay 81 from circuit. Relay 102 upon energization attracts its armature 105 to the contact 106 to complete. the cord circuit and attracts armature 114 to contact 113 to close the following circuit: from positive side of battery 14 to conduc tor 142, to armature 114 and-contact 113, conductor 143, winding 115 of the supervisory relay 116, conductor 144, contacts 118 and 111 of the relay 107, conductor 145 to repeating coil winding 91, cord strand 146, tip spring 89, tip 20 of plug 16, cord strand 29 through key R to conductor 130, through key K to conductor 131, through armature 52 and contact 57 of relay 24 to conductor 58, through supervisory relay 59, through conductor 55', through contact 54 and armature 51 of relay 54, through conductor 132,

I through conductor 133, through key R to cord strand 30, to jack spring 90, to cord strand 147, through repeating coil winding 92, through conductor 148, through contacts 119 and 112 of the relay 107, through conductor 149 and through winding 117 of the supervisory relay 116 to the negative side of battery 14, the superthrough the spring 79 upon energization (115C011?- visory relays 116 and 59 becoming energized and the local circuit, including the lamp 60 at the toll board, becoming closed to indicate to the toll operator that connection with the line to be called has been made. It will be noted that the relay 24 does not become energized upon connection of the toll plug 16 with the trunk jack, as the thimble 150 of this jack is dead. The trunk operator may send signaling currerft to ring the substation C by actuation of the springs 100 and 101 into engagement with the contacts 98 and 99, which may be connected with some source of ringing current, or the toll operator upon illumination of the lamp 60 may actuate her key R to send current from the generator 33 into and through the trunk cord M to ring the sub-station C. Upon removal of the receiverfrom the hook at sub-station C in answer to the ringing current, the circuit will be closed through the relay 107 as follows: positive side of battery 14, conductor 151, relay 107, conductor 152, contact 106 and armature 105, through springs 104 and 100, cord strand 153, through the plug and associated jack, line limb-(Z, through receiver circuit at the sub-station C through line limb 0, jack and associated plug to sleeve strand 140, to spring 101 and 103, through relay 102 and conductor 141 to bat- ...tery 14; relay 107 becoming energized attracts its armatures to engage the contacts 111 and 112 and to break connectlon between these contacts through the contacts 118 and 119. Tihe relay 59 at the toll station will now be disconnected fromcircuit and the lamp controlled thereby extinguished to indicate to the operator that the called substation C has answered. Circuit through the windings 117 and 115 of the trunk supervisory 116, however, will be maintained through the conductor 110 connecting the itIIl'lfitHfGS of the relay 107, the circuit being as follows: negative side of battery 14, wind; ing 117, conductor 149, armature 109, conductor 110, armature 108, contact 111, conductor 144, winding 115, conductor 143 and through armature 114 of relay 102, through conductor 142'to the positive side of battery 14. The connected connection for telephonic conversation.

As before described the condensers 46 and 48 complete the telephonic circuit through the toll cords and telephonic currents from the sub-station A pass into the trunk line and through the repeating windings 91 and 92 to be repeated into the windings 95 and 96 and to the sub-station C, and .vice versa voice currents from sub-station Q pass through repeating windings 95 and 96 and are repeated into the windings 91 and 92 and through the toll cords to substation Aand the condensers 46 and 48 serving also subscribers are now in ounces to prevent the-constant current which 0p crates re1ay.59--fr'0m passing out on theiline to thesub-station.

Upon completion of conversation the-sub scriber at sub-station .A upon actuation of his generator sends clearing-out current which results in the actuation-ofsupervisony relay 68 and the supervisory lamp controlled thereby, as before described. At suh-station w it is necessary only to -hang the receiver on the hook, whereupon the circuit before traced through'the sub-station and through therelay 107 is opened and the relay becomesdeenerg'ized and its armatures and contacts restored to their normal position so thatcu'rrent will again flow, as before described, through the toll supervisory relay 59 to cause the lamp 60 to, glow, which indicates .to the toll. operator thatthe apparatus at sub-station C has'been restored to normal. I

The operators key is normally connected across the plug. strands, .and the operator, upon actuation of the key, is normally con nectedwith bot-h sub-stations. It is sometimes desirable, however, that she connect with one subscriber only, as, for instance, where-the-connected subscribers fail'rto understand each other, when she mustconnect first with one subscriber and then with the other to assist in transmitting the messages. It is for this purpose that the auxiliary key K is provided. Upon actuation'of the key K to spread the springs 40 and ll, the connection between the operators set andthe cord strands leading to the substation A. is broken and the operator is then'connected only with sub-station B. IVhen the other .side of the key is'actuated theoperator will be connected'with sub-stati on A only. As the supervisory. relay 68 is also connected with the cord strands through the contacts of key K this relay will also be disconnected from the sameside-with the operators set. It is, however, desirable that supervision of the disconnected lineshould be maintained, and this temporary super vision is performed by the relay 59, which uponactuation of either side of the key K is connected in bridge of the cord strands on that side and the operator by-observing the lamp 60 can then receive any messages from sub-station A while she is connected only with sub-station B...

I thus provide a system of cordwircuit connections and arrangements which is greatly simplified over the systems heretofore used, inthatiless apparatus is usedand each'of the apparatus which is used being adapted to perform-several functions. The toll station operator has complete supervision at all'tiines, whether a toll sub-station connects with another toll sub-station, or a toll sub-station 18 connected with aconimon connected from battery-or, local-station, or .for any.oth.er.connections through her. cord. circuit.

As change may readilybe made in the detail arrangement'of the apparatus and cir cuits, I do not wishtobe limited to.the.exact arrangement here shown, but

1 claim as new and desire to secure by "ephone lines leading therefrom and termia cord circuit;at the nating in substations, exchange, a supervisory relay normally disthe cord circuit, a controlling relayfor controllin the connection of said supervisory relay with the cord circuit,"

connection of the cordcircuit with a line causing change in the circuit conditions for the controlling relay whereby said relay is actuated to connect the supervisory relay with the cord circuit, and a source of current at the substation adapted for connection with the line to send current through the supervisory relay when said relay is connected with the cord circuit.

3. In a telephone exchange system, the combination with a central exchange, of telephonelines leading therefrom and terminating in substations, a cord circuit at .the exchange, a supervisory'relay normally disconnected'from the cord circuit, a controlling relay for controlling the connection of said supervisory relay with the cord C11- cuit, connection of the cord circuit with a line causing ch'angein for the controlling relay .whereby said relay is actuated toconnect the supervisory relay withthe cord circuit, a source of alternating current at the substations adapted uponactuation to send current through said supervisory relay when sald relay is connected with'thecordcircuit, and a local energizing circuit 'for maintaining energization of the supervisory relay upon cessation of current flow from said source atthe substation.

the circuit conditions 4:. In a telephone exchange system, the

combination with a central exchange, of a telephone line leading :therefrom and terminating in a substation, .a cord circuitat the exchange, a supervisory relay normally disconnected from .the cord circuit, a relay cord circuit with the line ,for causing a 'cu'it with the line for closing a local circuit connected with the cord circuit. I

nected with the cord circuit, and a local for controlling said supervisory relay, and] means adapted upon connection of the cord circuit with the line for closing a local circuit through said controlling relay to cause actuation thereof to connect the supervisory relay with the cord circuit.

5. In a telephone exchange system, the combination with a central exchange, of a telephone line leading therefrom and terminating in a substation, a cord circuit at the exchange, a supervisory relay normally disconnected from the cord'circuit, a' relay for controlling said supervisory relay, means adaptedupon connection of the cord cirthrough said controlling relay to cause actuation thereof to connect the supervisory relay with the cord circuit, and a source of current at the substation adapted for connection with the line to send current through the supervisory relay when said relay is 6. In a telephone exchange system, the combination 'with a central exchange, of a telephone line-leading therefrom and terminating in a substation, a cord circuit at the exchange, a supervisory relay normally disconnected from the cord circuit, a relay for controlling said supervisory relay, means adapted upon connection of the cord circuit with the line for closing a local circuit through said controlling relay to cause actuation thereof to connect the supervisory relay with the cord circuit, a source of alternating current at the substations adapted upon actuation to send current through said supervisory relay when said relay is 0011- energizing circuit for maintaining energization of the supervisory relay upon cessation of current flow'from said source at the substation.

7. In a telephone exchange system, the combination with a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting telephone lines together, a supervisory relay normally disconnected from the cord circuit, a controlling relay for said supervisory relay, and means adapted upon connection of the cord circuit with the line for causing a change in the circuit conditions of said controlling relay to cause actuation thereof to connect the supervisory relay in bridge of the telephonic limbs of the cord circuit.

8. In a telephone exchange system, the combination With a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting telephone lines together, a supervisory relay normally disconnected from the cord circuit, a controlling relay for said supervisory relay, means adapted upon connection of the change in the circuit conditions of said controlling relay to cause actuation thereof to connect the supervisory relay in bridge of the telephonic limbs of the cord circuit, and a source of current at the substation adapted for through the supervisory relay when said relay is connected with the cord circuit.

9. In a telephone exchange system, the combination with a central exchange. of a substation connected therewith through a telephone line, a cord circuit for connecting telephone lines together, a supervisory relay normally disconnected from the cord circuit,

a controlling relay for said supervisory relay 7 means adapted upon connection of the cord circuit with the line for causing a change in the circuit conditions of said controlling relay to cause actuation thereof to connect the supervisory relay in bridge of the telephonic limbs of the cord'circuit, a source of alternating current at the substations adapted upon actuation to send current through said supervisory relay when saidrelay is connected with the cord circuit, and a local energizing circuit for maintaining energization of the supervisory relay upon cessation of current flow from said source at the substation.

10. In a telephone exchange system, the combination with a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting different telephone lines together. a supervisory relay for said cord circuit normally disconnected therefrom, a controlling relay for said supervisory relay, and an auxiliary contact forsaid cord circuit, said auxiliary contact engaging with the. spring jack thimble upon connection of the cord circuit with the line whereby a circuit is closed through the controlling relay to cause the supervisory relay to be connected in bridge of the cord telephone limbs of the cord circuit, said supervisory relay being thereafter controlled by substation apparatus.

11. In a telephone exchange system, thecombination with a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting different lines together for conversation, a

supervisory relay normally disconnected from the cord circuit, a controlling relay for said supervisory relay, an indicating signal normally connected with the line limbs, a cut off relay for controlling the connection of connection with the line to send current said indicating signal with theline limbs,

and a local circuit closed upon connection of the cord circuit with the line, said local circuit including said cut cit relay and said controlling relay to cause actuation thereof, said out off relay upon actuation causing the indicating signal to be disconnected from the line limbs and actuation of the controllingsupervisory combination with relay causing said supervisory relay to be connected with'the cord circuit to be thereafter controlled by substation apparatus,

12. In a telephone exchange system, the combination with a central exchange, oiv a substation connected therewith through a said indicatingsignal with the line limbs,

and a local circuit closed upon connection of the cord circuit with the line, said local circuit including said cut off relay and said controlling relay to cause actuation thereof, said cut off relay upon actuation causing the indicating signal to line limbs, actuation of said controlling relay causing said supervisory relay to be con nected in bridge of the telephonic limbs of the cord circuit and the line limbs connected therewith, said supervisory relay being thereafter controlled by substation apparatus.

13. In a telephone exchange system, the a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting different lines together for conversation, a relay normally disconnected from the cord circuit, a controlling relay for said supervisory relay, an indicating signal normally connected with the line limbs, a cut oil relay for controlling the connection of said indicating signal with the line limbs, and a local circuit closed upon connection of the cordcircuit with the line, said local circuit including said out oii relay and said controlling relay to causeactuation thereof,

' said out off relay upon actuation causing the indicating signal to be disconnected from the line limbs, actuation of said controlling relay causing said supervisory relay to be connected with the cord circuit and line connected-therewlth, and a source of current at the connected substation adapted to send current through said line and connected su pervisory relay.

14. In a. telephone exchange system, the combination with a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting different lines together for conversation, a supervisory relay .normally disconnected from the cord circuit, a controlling relay for said supervisory relay, an indicating signal normally connected with the line limbs, a cut off relay for controlling the connection of said indicating signal with the line limbs,

a local circuit closed u on connection of the cord circuit with the line, said local circuit including said out ofi relay and said conbe disconnected from the impulse through the combination with a central exchange,

trolling relay to cause actuation thereof,-said cut 01f relay upon actuation causing the indicatin signal to be disconnected from the line limbs, actuation of said controlling relay causing said supervisory relay to be connected with the cord circuit, a source of alternating current at the connected substation, actuation of said source causing current 1 to travelthrough the line'and supervisory relay connected with the cord circuit, a supervisory signal circuit controlled by said supervisory relay and closed upon energizat-ion thereof, and a local circuit for said supervisory relay for maintaining energization thereof and closure of the supervisory signal circuit upon disconnection of said source at the substation.

15. In a telephone exchange system, the

combination with a central exchange, of a substation connected therewith through a telephone line, a cord circuit for connecting different lines together for conversation, a supervisory relay normally disconnected from the cord circuit, a controlling relay for said supervisory relay, normally connected with the'line limbs,-a cut as relay for controlling the connection of said indicating signal with the line limbs, a local circuit closed upon connection of the cord circuit with the line, said local circuit including said out ofi relay and said controlling relay to cause actuation thereof, said out off relay upon actuation causing the indicating signal to be disconnected from the line limbs, actuation of said controlling relay causing a winding of said supervisory relay to be connected in bridge of the telephonic limbs ofv the cord circuit and with the limbs of the connected telephone line, a generator at the substation for sending an line and supervisory relay winding connected with the cord circuit, a supervisory signal circuit closed upon initial energization of the supervisory relay, and a local circuit for said supervisory relay for naintaining energization thereof upon disconnection of. the generator 16. In a telephone exchange system, the

of substations connected therewith and with telephone lines, a cord circuit provided with plugs ror connection with springjacks connected with the lines, a supervisory relay normally a. controlling relay associated with each plug for controlling said supervisory relay, connection of a plug with a line causing closure of a local circuit through the corresponding controlling relay to'connect the supervisory.

stations connected therewith through telean indicating signal from the line.

disconnected from the cord circuit,

'relays associated with lions for controlling phone lines, a cord circuit provided With plugs for connecting lines together, a supervisory relay normally disconnected from the cord circuit, a controlling relay associated with each plug of the cord circuit, connection of said plugs with springjacks connected with telephone lines to be connected causing closure of a local circuit to reach the controllingrelay whereby said supervisory relay is connected with the cord circuit, a source of (an-rent for supplying said local circuit, and means at the connected substasaid supervisory relay after connection thereof with the cord circuit.

18. In a telephone exchange system, the combination with a central exchange, of substations connected therewith through tele phone lines, a cord circuit at the central exchange, a supervisory relay normally connect ed. with the cord circuit, a second supervisory relay normally disconnected from the,

cord circuit, and means upon connection of said cord circuit with a telephone line causing disconnection of the first supervisory relay from the cord circuit and connection of the second StlPcl'YlSOIy relay With the cord circuit.

19. In a telephone exchange system, the combination with a cord circuit for connecting the telephone lines, of a supervisory relay normally connected to the cord circuit, a second supervisory relay normally disconnected from the cord circuit, and means adapted upon connection of said cord cir cui t with a telephone line to cause disconnection of the first relay from the cord circuit and connection with the second supervisory relay in bridge of the cord circuit conductors.

20. Ina telephone exchange system, the combination with a cord circuit for connection with telephone lines, of two supervisory the cord circuit, a normally disposed to connect one of said supervisory, relays With the cord circuit and to disconnect the other supervisory relay from the cord circuit, said controlling relay being actuated uponconnection of the cord circuit with a line to dis connect the first supervisory-relay from the cord circuit and to connect the second supervisory relay therewith.

21. In a telephoneexchange system, \the combination with a cord circuit for connecting telephone lines together, of a supervisory relay normally connected in bridge of cord circuit conductors, a second supervisory relay normally disconnected from the cord circuit, and a controlling relay for disconnecting said first supervisory relay from the cord circuit and for connecting said second supervisory relay in bridge of cord circuit conductors.

controlling relay controlling relays,

22. In a telephone exchange system, the combination with a cord circuit for connecting telephonelines together, of a supervisory relay normally connected in bridge of cord circuit conductors, a second supervisory relay normally disconnected from the cord circuit. and a controlling relay adapted upon connection of the cord circuit with a. line for causing disconnection of the first supervisory relay from thecord circuit and connection of the second supervisory relay in bridge of cord circuit conductors.

23. In a telephone exchange system, the combination with a cord circuit terminating in two plugs, of cord strands connecting said plugs, a condenser in each cord strand dividing the cord circuit into two conductively distinct sections, a supervisory relay normally connected with both sections, a second supervisory relay normally disconnected from either section. and a controlling relay associatedwith each section, connection of a plug with a telephone'line causing actuation. of the corresponding controlling relay to disconnect the first supervisory relay from the corresponding section and to connect the second supervisoryrelay with said section.

In a telephone exchange system, the combination with a cord circuit terminating in two plugs, of tip and sleeve strands connecting said plugs, condensers for dividing said cord circuit into two corductively distinct sections, a supervisory relay normally connected in both sections, a second supervisory relay nor- .mally disconnected from the cord circuit,

and a controlling relay associated with each cord section, connection of a plug with a telephone line causing actuation of the corresponding controlling relay to disconnect the first supervisory relayfrom the cord circuit and to connect the second supervisory relay in bridge of the cord strandsof the correspending section.

25. Ina telephone exchange system, the combination with a cord circuit for connecting telephone lines, together, of two plugs for said cord circuit, tip and'sleeve strands connecting said plugs together, condensers for dividing said cord circuit into'two conductively distinct sections, a controlling relay for eachv section, a source of current, a supervisory relay normally connected in bridge of both cord sections, twocontactsof the a second supervisory relay normally disconnected from the cord circuit, connection of a plug with a line causing closure of a circuit including said source of current and the corresponding controlling relay whereby said relay is actuated to disconnect the first supervisory relay from the corresponding section and to connect the secondsuper'visory relay in bridge of said section.

bridge of the cord strands of t 26. In a telephone "the combination with a cordcircuit' for connect ing, telephonelines together,- two plu for said cord circu'it, t-ip and sleevestraii sconnected with'the telephone lines,

'necting said'xplu'gs together, condensers for dlvidin said cord circuit into two conductively' istinctfjsections, springjacks; contact for each plug, a spring acklcontact for connection with .said auxi iary contacts, a

controlling relay for eachsection connected with the corresponding thirdzcontact, a source of current, a supervisory relay'nor-- mallywconnectedwith both sections of the cord circuit through contacts, of said cont-rollin -rela'ys,, 'a second supervisory relay norma disconnected from the cord circuit by said controlling relays,- connection of a plugwith-aspringjack causing closure of a local circuit. through said source of current and correspondingcontrolling relay, 'whereby said controlling relay is actuated to disconnect he first supervisory relay from the corresponding section and-to connect the second superviso relay with said section, said second SHPBIVISOI'Y relay being thereafter controlled 'byjapparatus at the connected substation.

27. Inr'a telepho'ne exchange system, the

combination with a central exchange, of telephone .linesleading therefrom and-terminating in;substations,a cord circuit forconnecting telephone lines together, a supervisory relay normally disconnected from the cordcircuit, means adapted upon connection oft-h'ejcord circuit with a line for connecting said supervisory relay with the cord circuit, operators telephonic apparatus normally associated with both plugs of the cord-circuit, a second supervisory relay, anda key, actuation ofsald key causingdisassociation of the oper'ators telephone apparatus from one plug of the cord circuit and I disconnection fron the cord circuit of the first supervisory relay, said key upon actuation causing also said second supervisory relay to be supstituted for'the disconnected supervisory re ay. t

2-8. In a telephone exchange system, the

combination with a cord circuit for connect ing telcphone'lines together, a supervisory v relay normally connected with the cord cirdisconnected from' the cord circuit, and

cuit, a second supervlsory relay normally means adapted upon actuationto disconnect the first supervisory relay from the cord circuit and to substitute therefor the second supervisory relay. c

29. In'a telephone exchange system the combinationwith a cord circuit terminating in plugs engaging with springjacks connected with telephonelines, said cord circuit being divided into two conductively' distinct sections, operators telephonic apparatus nora third conmallyconnected 'with both'sections, a super visory relay common to bothqsections, a key,- and as'econd supervisory relay normally dis-1' connected from the cord circuit, actuation of said key in'one direction causing disconnection v of the operators telephonic apparatus and said first supervisory relay rom the corresponding cord. section and connection ofsaid second supervisory relay with said section. v H

' 30. In a telephone exchange 'system, the

cuit for connecting'o'the'r telephone lines with ,75 combination with a trunk circuitior c'onmeeting with telephone line's,of a cord cir-j said trunk circuit, a supervisory relay con- 1 .nected with the cord circuit, connection oi-said cord circuit with the trunk circuitv causing' closure of a circuit through said supervisory a controlling relay associated with- ,Ythe

relay, trunk circuit, and apparatusrat the substation connectedwith the trunk circuit adapted' upon actuation to close a circuit through the controlling relay whereby said relayis operated to open the supervisory relay circuit.

31; In a telephoneexchange system, the combination with a trunk circuit for connecting with telephone lines, of a cord circuit for connecting other telephone lines with said trunk circuit, a controlling relay at the necting with telephone lines, of a cord circuit for connecting other telephone lines with said trunk circuit, a controlling relay at the .trunk circuit, a supervisory relay connected in bridge of the cord circuit, connection of said cord circuit withthe trunk circuit causing closure of an energizing circuit through said supervisory relay and through contacts of said controlling relay, said controlling relay being under control of apparatus at the substation connected with the trunk line.

33. In a telephone exchange system, the combination with a trunk circuit for connecting telephone lines leading to substations, of

a cord circuit for connecting other telephone lines with said trunk circuit, a controlling 'rela of the trunk circuit controlled by sublis stat on apparatus after connection of the trunk circuit with the line, a supervisoryrelay for the trunk circuit, a supervisory relay for the cord circuit, connection of said cord circuit with the trunk circuit causing closureof ail-energizing circuit through 'said' supervisory relays, said controlling relay upon respongc to substation -21pparatns-be1ng adapted to disconnect the :cord circuit sup0r visoi'y relay and to maintain the circuit through the U'UDk CiBCH it su'perviscry relay.

In witness whereof, I hereunto subscribe my name this 22nd day" of Jtmuary A. 1906, hlERRLT" S. CUNNER Titnesses C ARLES J 8011mm, -LEONARD W. Novnxmsiz. 

